Yeah I have a T480S and it barely runs WoW Classic. I’ll sometimes do light games the iGPU is capable of. Most of the time I use my desktop to run games, and if I want to play it on this machine, I’ll use Moonlight and Sunshine to stream over to it from the desktop. That machine is a 3090 paired with a 12700KF though. It runs whatever I want it to.
I don’t have off-LAN game streaming working entirely just yet, but with ZeroTier you can theoretically run everything remotely - my upload speed is probably the limiting factor there, but the internet works well enough otherwise for Plex streaming off-LAN.
A Deck would probably run FFXIV pretty well, and with the form factor of a controller that you’re used to playing with.